III. Multiple Choice

For questions 1-5 use a normal random variable X with mean sixty and standard deviation six.

1.Calculate the Z-score for x = 52.

a. 1.33b. 0.4082c. -1.33d. 0.0918e. not given

2.Determine the value of x that is equivalent to a Z-score of 1.96.

a. 67.96b. 61.96c. 48.24d. 76.71e. not given

3.Find the probability that x is between forty-five and seventy.

a. 0.9587b. 0.0062c. 0.0537d. 0.9463e. not given

4.Give the probability that x is at most 78.5.

a. 0.999b. 0.4990c. 3.08d. 0.001e. not given

5.What is the value of x such that P (X < x) is 0.3023?

a. 0.85b. 52.9c. 65.1d. -0.85e. not given

6.Look up the value for P(Z>1.96).

a. 0.9750b. 0.4500c. 0.0250d. 0.4750e. not given

7.Which value for z satisfies P(Z

a. -0.44b. 0.954c. 0.44d. 0.7486e. not given

8.Choose the correct standard error for x-bar if s^2 = 5.4756 and n = 36.

a. 0.5121b. 0.39c. 0.9126d. 0.065e. not given

9.Calculate the z-score for x = 58 if x-bar is 70 and s is 5.

a. 0.0082b. -2.4c. 2.4d. -0.4918e. not given

10.Determine P(-1.23

a. 0.3907b. 0.1736c. 0.5643d. 0.2171e. not given

11.In a population of normally distributed aptitude scores of 1000 academy students with mean 70 and Standard deviation 10, how many score above 95?

a. 494b. 6c. 25d. 250e. not given

12.The z-score for x-bar = 2.7, mu = 3, s = 0.1, and n = 100 is:

a. -30b. -3c. -0.3d. 3e. not given

13.Find a 95% confidence interval for mu if s = 5.26, x-bar = 70.1, and n = 49.

a. 70.1+/-0.2104b. 70.1+/-1.2361c. 70.1+/-1.4728d. 70.1+/-1.6772e. not given

14.Compute a 99% confidence interval for mu if x-bar = 16.3, s = 1.5, and n = 25.

a. 16.3+/-0.8391b. 16.3+/-0.774c. 16.3+/-0.8361d. 16.3+/-0.16782e. not given

15.Assume Ho: mu

a. 1.414b. 0.483c. 0.017d. 2.12e. not given

16.A company claims a mean battery life of 42 months.A sample of 36 yields a mean of 39 months with a standard deviation of 7 months.Test the null hypothesis, Ho: mu >/=42 with alpha 0.05.

a. Fail to reject Hob. Reject Hoc. Fail to reject Had. Reject Hae. not given